The proposed work involves 1) isolation and purification of growth hormone from pituitaries of pigeon, and one (possibly 2) teleost fish; 2) further chemical and physical characterization of canine, porcine and monkey growth hormones; 3) systematic studies of alteration of structure of porcine and bovine GH by progressive deamidation, to investigate the part net charge may play in immunochemical and biologic specificity; 4) further work on the isolation of "high-prolacting" fractions of human growth hormone, in order a) to see whether a practical "Pseudo-prolactin" low in growth activity can be prepared, which might have experimental or therapeutic utility and b) to try to understand the structural requirements for prolactin activity of hGH; 5) to complete studies on the isolation and characterization of porcine prolactin; 6) to continue studies of the relation of structure and function in human growth hormone.